I learned this lesson accidentally. I was showing a friend a new card trick I'd made up, fanned the cards and asked him to pick one, remember it and replace it

I learned this lesson accidentally. I was showing a friend a new card trick I'd made up, fanned the cards and asked him to pick one, remember it and replace it into the deck. As he did that I got confused - I thought I'd gone wrong and, apologising, asked him to pick another card. Fanned the cards again and he looked down at them to pick another one. In the middle of the fan, staring right back at him one card was face up; the card he'd chosen the first time. I hadn't gone wrong at all, the trick had gone perfectly - I was just confused and thought I'd gone wrong when I hadnt. It wasn't the plot line I'd originally had in mind for the trick, but it blew him away because when he went to pick a card the second time he wasn't expecting to see the card he picked the first time. The surprise was a huge contributing factor to the impact of the trick.